Screw this American seven-years-and-out model. The BBC's new Doctor Who series can run for another 20-plus years, just like the original version, says producer Russell T. Davies. The key is taking an occasional pause, like in 2009, when the show will only have three one-hour specials. Also, it wouldn't hurt to bring… »3/11/08 6:30am 3/11/08 6:30am